Sphan519

Does the battery light still come on when you rev past 5k rpm?

CharlieD93

Not with the new alternator I got, I still have the Mechman alternator. I am going to put it on my girlfriend's IS300, I believe they have the same set up, so they alternator should fit in hers. Once I finally install it on hers, I will do the rev test (that's what I call it). I will know if it is the alternator or the car at that point.

Sphan519

My battery light still comes on if i go past 5k rpm, so when im on the freeway gunning it, the light will stay on once the needle goes past 5k until it shifts. I don't notice any difference in the power, my sub still pounds. nothing irregular

CharlieD93

Yeah I don't the battery light is a real problem, maybe a precautionary or maybe the computer actually thinks it is getting more Volts (i.e 14.5+ volts) since the amperage is much higher. Just a thought. I still get massive voltage drops, I beginning to believe in bad ground (THAT I CAN'T FIND), a bad wiring harness (I have no bottom engine cover, maybe something get on cut, scraped, or soaked in rain water), or the battery. I haven't been able to change batteries since I have been extremely busy. Maybe I can go buy a new battery this weekend, new battery terminals and see what happens.

bsmith203

iTrader: (1)

I stumbled upon this thread while searching for people's experiences with high output alternators. My stock alternator is holding up fairly well under the insane load my 1800 rms watt system is putting on it, however I know I'm not getting all of the power out of my amps as I should since I done have the proper current/amps to feed them. Seems as if the mechman alternators are not being properly bench tested and going through QA prior to being received by customers. I'm not a mechanic and can't imagine spending $450 on a alternator plus $250 for install just to have to repay $250 for labor to have it uninstalled to send back then another $250 for reinstall for the piece still not work properly. Charlie is the shipping fee the biggest reason you don't want to send it back to mechman? What alternator did you replace it with that is not currently giving you any issues?

CharlieD93

Any alternator besides this Mechman alternator that I have works just fine and does not bring up my battery light past 5k rpms. I bought a a Quality Built alternator for the time being, It holds at 14.4 volts when warm or cold until I come to a stop and my rpms are down to 500 or under then the alternator shuts off and I am running on battery. I do not think this is an alternator issue but more of a mechanical issue since when my rpms go back up past 520 rpms the alternator kicks back on and I am seeing 14.4 volts. It didn't cost me 250 for install, only 60 bucks since I know the mechanic very well. I got tired of going to the mechanic, so I bought a belt tensioner tool, and starting taking off the alternator myself. Literally 20-30 minute job now. I have read the DC Power alternators work really well with our cars. My rpm issue is my IAC valve/motor going out. Sounds like paper shredding when I rev the engine, so I will be getting a new one soon and then putting the Mechman alternator back on, if the IAC motor fixes my rpm issue. I can only hope so. It only cost 15 bucks to send it back, but I do not think it is an alternator issue at this point. Someone told me that it could be the charging system cutting off so the extra amps don't hurt the car, just a thought, sounded like it could be that, just not sure. Hope this helps you.

bsmith203

iTrader: (1)

Any updates Charlie as to replacing thvalue and reinstalling the mechman in your ride? Or did you put it in your girlfriends IS?

JimBobNC

Everyone: Please don't overlook the mechanical aspect of this problem. If you can create the problem in your driveway, check to see how the engine is reacting when the light illuminates. Be sure your cables are not being pulled during this transient.

CharlieD93

I have not installed it into my girlfriend's car as of yet, she is hesitant to install it since she believes it will mess up her car as well. I keep telling her it's my car that's boned, so hers would be fine. For value, I stated that in my last post, but it only cost me 180 bucks (went 3 times to my mechanic to uninstall/reinstall.) Then I started doing it myself, so it doesn't cost me anything now, 30 minutes is what it cost. She goes out of town this weekend with her car, so I don't want to mess up somehow anyway, so I will be putting it in next weekend (the 21st) and will update. I just have not had the time either to do anything with work. JimBob, what exactly are you talking about? Cables as in power/ground cables? They aren't being pulled at all. I have noticed if I let my car sit for a day or 2, that it is hard to crank at first, then turn key off position, turn the key back on position and it cranks. I do to need have my starter and IAC motor checked, and possibly a new battery, but not in the right position to buy that items right now. Probably a few weeks away from buying all that or at least 2 weeks away to get the IAC motor. I WILL update if/when I get my car working right. Who knows, could be a leaking capacitor which I will never find, but will have to bring to Lexus and have them diagnose the problem; trying to avoid the dealership at all costs so I don't have to throw so much money.

bsmith203

iTrader: (1)

Did you ever reinstall the mechman alternator? If so did the issues disappear in your girls ride?

CharlieD93

Actually, I never got to install it into her car because we decided to split up. So I do not know if it is an alternator issue or my car is the issue. I am selling the alternator at this point as I am getting a new car as well, I did fix the rpm and voltage issues by getting a new IACV. If someone wants to figure it out or might have a different experience with their GS, then they can pm me to buy the alternator. It is Mechman 240 Amp that still looks new, maybe 6 hours in my car at the most. So sorry for not answering this problem alternator wise.

Sc0pe

iTrader: (1)

I installed a 320A Mechman on my 1999 LS400 over the weekend, and I also have a battery light on my dash. Unlike the OP, mine stays on constantly instead of briefly coming on under load. My install consists of the alternator itself, a 1/0 power cable (alternator positive to battery positive) fused for 350A, and I have also grounded the alternator case to the chassis with 1/0 cable as well.